How bonuses are taxed

A bonus is not taxed at a special rate

There is no bonus tax in the UK. A bonus is employment income like any other, taxed at your ordinary band rates and subject to National Insurance and student loan deductions in the normal way. Over a full tax year, a £5,000 bonus on a £45,000 salary costs precisely what an extra £5,000 of salary would cost: £1,000 in income tax at 20%, leaving £3,600 after National Insurance.

The confusion comes from timing, not from rates.

Why the bonus month looks brutal

PAYE is cumulative. Each month your employer releases one twelfth of your personal allowance and one twelfth of your basic rate band, then charges tax on your total pay for the year to date and subtracts what you have already paid. In month one you have had £1,047.50 of allowance and £3,141.67 of basic rate band, and nothing more.

Take someone on £45,000 who receives a £10,000 bonus in April, the first month of the tax year. Their pay that month is £13,750. After one month of allowance, £12,702.50 is taxable. Only £3,141.67 of that fits in the basic rate band, so £9,560.83 is taxed at 40%. The month one tax bill is £4,452.66.

That figure is correct under the rules and completely misleading as a picture of the year. The true annual tax on £55,000 is £9,432. Because £4,452.66 has already been paid, the remaining eleven months only need to collect £4,979.34, roughly £453 a month against the £541 a month a bonus-free year would have produced. The overpayment unwinds itself month by month, and by the following March the total is exactly right.

The National Insurance surprise

National Insurance runs the other way, and in your favour. It is charged on each pay period in isolation against monthly thresholds, and it is never reconciled across the year. That means a large one-off payment can push earnings above the monthly upper earnings limit of £4,189, where the rate falls from 8% to 2%.

This is a genuine, permanent saving rather than a timing effect, and it is the reason asking for a bonus to be paid in instalments is usually the wrong instinct.

When you have genuinely been overtaxed

Cumulative PAYE self-corrects. Three situations break that.

• An emergency code. If your code ends in W1, M1 or X, each pay period is taxed in isolation and the overpayment never unwinds through payroll. This is common when a bonus lands soon after starting a new job.
• A bonus late in the tax year followed by leaving. If March pays a big bonus and you then have no employment income in the new tax year, there are no later payslips to absorb the correction.
• A wrong tax code. A 0T or BR code applied to the bonus payment removes your allowance entirely.

In each case the money comes back, but through HMRC rather than payroll. Check your personal tax account, look for a P800 calculation after the tax year ends, or claim directly through gov.uk. Getting the code corrected first is usually faster than waiting for the year-end reconciliation. See tax codes explained for how.

Sacrificing a bonus into your pension

Bonus sacrifice is the same mechanism as salary sacrifice applied to a one-off payment. You agree, before you become contractually entitled to the bonus, to give it up in exchange for an employer pension contribution of equivalent value. Because the money never becomes your earnings, neither income tax nor National Insurance applies, and the employer saves its 15% secondary contribution too.

The timing rule matters. If the agreement is made after entitlement arises, HMRC treats it as a redirection of earnings you already own, and tax and National Insurance are due anyway. Employers who run bonus sacrifice properly ask for elections weeks before the bonus is announced.

The value depends on where the bonus sits in your income. A basic-rate taxpayer saves 28p in the pound. A higher-rate taxpayer saves 42p. Someone whose bonus pushes income through £100,000 saves around 62p in the pound because the personal allowance taper is reversed as well - the single strongest case for bonus sacrifice in the whole system, and the reason the 60% tax trap is worth understanding before your bonus is confirmed.

Things worth checking before the bonus lands

1. Your tax code. A cumulative code means the arithmetic sorts itself out. An emergency code means it will not.
2. Whether the bonus pushes your total income over £50,270, £100,000 or £125,140. Each of those crossings changes the marginal cost sharply.
3. Your pension annual allowance. A large sacrifice can breach it, particularly if your allowance is tapered.
4. Child benefit and childcare thresholds, which are driven by adjusted net income and can be crossed by a single bonus payment.
5. Your student loan deduction. It is charged on the bonus in the month it is paid, at 9% or 15% of the amount above the monthly threshold.

Model it first

The take-home pay calculator has a bonus field. Enter your salary and bonus together to see the true annual cost, then add a pension percentage under salary sacrifice to see what redirecting the bonus would be worth. That is a far better guide to the decision than a single alarming payslip.

Common questions